Compound ejector

ABSTRACT

Apparatus and methods of operation are disclosed for combining injected high-energy primary flow fluid (normally a gaseous medium) and induced or entrained secondary flow fluid (frequently air) at and in the essentially conventional throat and diffuser sections of an ejector to significantly increase ejector performance efficient with limited injection slots or openings of limited size and with minimum diffuser lengths, to achieve high diffusion rates and substantially reduced system energy losses attributed to fluid flow blockage and flow separation, and to obtain other important ejector operating characteristics.

O United States Patent [111 3,885,891 Throndson May 27, 1975 [54]COMPOUND EJECTOR 1,235,302 5/1960 France ..4l7/197 [75] lnventor: LesterW. Throndson, Westerville, OTHER PUBLICATIONS Ohlo Experimental ThrustAugmentation of a Variable [73] Assignee: Rockwell InternationalCorporation, Geometry, Two-dimensional Coanda Wall Jet Ejec- Pittsburgh,Pa. tor W. J. Scott, January 1964 National Research [22] Filed Jan 111974 Council of Canada Aeronautical Report LR-394.

Appl. No.: 432,724

Related US. Application Data Continuation of Ser. No. 310,723, Nov. 30,1972, abandoned.

US. Cl 417/196; 417/197 Int. Cl F04f 5/44 Field of Search..... 60/264,269; 239/8, 265.17;

[56] References Cited UNITED STATES PATENTS 2,000,762 5/1935 Kraft417/167 3,047,208 7/1962 Coanda 239/D1G. 7

3,370,784 2/1968 Day r 417/167 3,694,107 9/1972 Stein 417/167 FOREIGNPATENTS OR APPLICATIONS 613,144 1/1961 Canada 417/197 Primary ExaminerM.Henson Wood, Jr. Assistant ExaminerJohn J. Love [57] ABSTRACT Apparatusand methods of operation are disclosed for combining injectedhigh-energy primary flow fluid (normally a gaseous medium) and inducedor entrained secondary flow fluid (frequently air) at and in theessentially conventional throat and diffuser sections of an ejector tosignificantly increase ejector performance efficient with limitedinjection slots or openings of limited size and with minimum diffuserlengths, to achieve high diffusion rates and substantially reducedsystem energy losses attributed to fluid flow blockage and flowseparation, and to obtain other important ejector operatingcharacteristics.

15 Claims, 5 Drawing Figures PATENTEUHAY 27 I975 SHEET HIGH ENERGY FLUIDSOURCE COMPOUND EJECTOR CROSS REFERENCES This is a continuation, ofapplication Ser. No. 310,723, filed Nov. 30, 1972, now abandoned.

SUMMARY OF THE INVENTION Ejector apparatus having conventional throatand diffuser sections in its operating configuration is provided withcenter injector means and additionally with Coanda injector means, andis operably connected to a source of high-energy primary flow fluid. Theinjected primary flow fluid from both said injector means is combinedwith entrained secondary flow fluid, induced through the ejector inletopening, at and in the ejector throat and diffuser sections to bothsignificantly increase ejector output force-to-input force performanceratio (thrust augmentation ratio) and minimize ejector system energylosses in comparison, for instance, to the performance of comparablysized and configured conventional multi-tube injector ejector apparatus.The invention achieves thrust augmentation ratios at least to as greatas approximately 1.55 employing a secondary flow entrance (slot) arearatio of approximately 12.5, and is especially significant with respectto short length ejector configurations wherein the desired ratio ofejector diffuser length to ejector throat diameter is in the range ofapproximately 1 to 2.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of anembodiment of the compound ejector of this invention having a throatsection with circular planform;

FIG. 2 is a schematic sectional view taken at line 2-2 of FIG. 1;

FIG. 3 is a schematic plan view of an embodiment of the compound ejectorof this invention having a throat section with a rectangular planform;

FIG. 4 is a schematic cross-sectional view taken at line 44 of FIG. 3;and

FIG. 5 graphically illustrates thrust augmentation ratio performanceachieved by the instant invention in comparison to thrust augmentationratio performance achieved with various conventional ejector apparatusarrangements.

DETAILED DESCRIPTION The embodiment of the invention illustratedschematically and in sectional detail in FIGS. 1 and 2 is distinguishedfrom the other embodiment illustrated in the drawings primarily by theplanform of the ejector throat configuration. The principal elementscomprising the FIG. 1 arrangement are separately described in thefollowing subparagraphs, each identified initially by the appropriatereference numeral in the drawings, and' additionally as to elementnomenclature, details of form and construction, and statement ofprincipal function or functions:

11; ejector high-energy fluid source; normally in the form of a sourceof pressurized gaseous medium at a pressure ratio of approximately 1.3or greater (e.g. 1.3 to 30 depending on type and location of sourceavailable) at the source discharge face such as a highpressure gassupply, a gas compressor, a turbofan engine fan, or a turbo-jet engineturbine section; provides primary flow fluid to the ejector and suchfluid may comprise, in some applications, products of combustion at anelevated temperature (e.g. 65C. to 600C.) relative to ambient oratmospheric temperature (nominal 15C.).

12; supply duct sections; normally of metallic construction or offibre-reinforced thermosetting resin construction and in conventionalduct cross-sectional configurations preferably sized to minimizeinternal fluid flow pressure or energy losses and to achieve flowvelocities of about 0.25 Mach Number in typical applications butsometimes to as great as about 0.4 Mach Number; directs primary flowfluid from source 11 to primary flow distribution ductwork:

13; distribution duct sections; similar in construction andcross-sectional configuration to duct sections 12; direct proportionedprimary flow fluid to system injectors;

14; duct fittings; similar in construction to duct sections 12 and 13and of conventional fitting configuration; join system duct sectionstogether and to other system fluid distribution elements;

15; primary flow control valve; essentially of metallic construction andconventional valve configuration but in some applications may take formof plug nozzle with cooperable diverter; regulates/diverts flow ofprimary flow fluid from source 11 through supply duct sections 16;proportioning valves; of conventional metallic construction andconfiguration; proportioning of primary flow fluid to minimize systemenergy losses preferably and normally is accomplished by varying ductdiameters of slot and nozzle opening sizes but if elements 16 areprovided in the ejector arrangement, such function to further controlthe primary flow fluid from source 11 for proper distribution. toindividual injectors in the apparatus, and in either case proportioningnormally is with from 30 to percent of totalprimary fluid flow to theejector center injector and the balance to the ejector Coanda injector;

l7; center injector; of streamlined duct-like or tubelike constructionusing materials comparable to the materials comprising duct sections 12and 13 and having a location above the ejector throat section and anoperating orientation downwardly along the, general flow direction ofthe ejector diffuser section; directs primary flow fluid to the centerof the ejector throat section for downward projection essentially alongthe ejector diffusersection flow axis; 18; nozzle opening; an opening inthe center injector sized to achieve a desired percentage primary fluidand a flow velocity approaching or in excess of approximately 0.7 MachNumber and located preferably slightly above or at the plane of theejector throat section; provides downward primary air flow at the hroacenter and at a proper velocity;

19; coanda injector supply duct; generally similar to injector means 17in construction materials but of annular planform configuration with thetoroidal inside diameter essentially corresponding to the ejector throatsection diameter and the toroidal average diameter corresponding to thediameter of the ejector circular inlet area; typically directs primaryflow fluid to the perimeter of the ejector inlet for injection intosystem 10, for approximately to 1 10 angular rotation (15 to 30minimum), and for mixing and downward proje tion essentially innonseparated relation to the diverging walls of the ejector diffusersection;

Coanda slot opening; ring-like slot opening in the Coanda injectorsupply duct substantially coextensive with the perimeter of the ejectorcircular inlet area and sized to achieve a primary fluid flow in thedesired to 70 percent total flow range and with a velocity approachingor in excess of approximately 0.7 Mach Number; the opening, by virtue ofits location and orientation essentially injects primary flow fluidradially inwardly toward the inlet area center and approximately atright angles to the lift ejector operating longitudinal axis whereuponit is rotated by the Coanda effect typically approximately 90 to 1 10into a downward path generally along the direction of the walls definingthe ejector divergent diffuser section; and

21; diffuser section wall; of metallic composition of fibre-reinforcedthermosetting resin composition in plate-like, circumferentiallycontinuous form and joined and faired to the wall of Coanda injectormeans 19 to provide a smooth transition from the ejector throat to thedivergent ejector diffuser section exit opening; length essentiallyaccomplishes mixing of ejector primary and secondary fluid flows anddiffusion allows pressures produced at the inlet to induce ejectorsecondary fluid flow and develop improved ejector thrust.

In addition, the drawings are provided with certain of the followingreference symbols identifying features or characteristics of the ejectorconstruction of the invention useful for analytical purposes:

L; ejector length (height); extends from the plane of the ejector exitopening to the plane of ejector inlet opening, the latter normally beingpositioned a relatively small distance above the plane of the ejectorthroat section;

D; ejector diameter; essentially the diameter of the ejector throatsection except that in cases of noncircular throat section planforms thedimension may correspond to the average planform dimension of the throatarea affected by the center injector and the ejector cross-section beinganalyzed; 1

A,;.; cross-sectional (planform) area of ejector throat section;

A,-; cross-sectional (planform) area of ejector inlet;

A;.; cross-sectional (planform) area of ejector exit;

A,,; cross-sectional area of primary fluid flow exits which in mostinstances is the sum of the discharge area of the center injector nozzleopening and the Coanda injector slot opening;

A cross-sectional area of secondary or entrained fluid flow which inmost instances, because of relative absence of blockage in the ejectorthroat section by the center injector means 17, essentially correspondsto the ejector inlet area A,; and

a; ejector diffuser section wall divergence angle (half-angle) relativeto the lift ejector axis in the general direction of principal fluidflow.

Heavied arrow showings in the drawings indicate principal air flowdirection for the primary, secondary, and combined fluid flows. Theejector discharge flow at the exit face is particularly noteworthy inview of the fact that it is substantially of improved distributionacross the exit face.

FIG. 3 illustrates an ejector apparatus embodiment 30 having thefeatures of this invention combined with supporting structure referencedgenerally as 31. In addition to a different throat section planform,those FIG. 3 (and FIG. 4) elements of the embodiment which differsignificantly from FIG. 1 and FIG. 2 in detail are as follows:

32; straight-line center injector; has characteristics, except forprincipal planform configuration, of center injector 17; directs primaryflow fluid in the operating position for downward projection essentiallyalong the ejector diffuser section flow axis;

33; slot opening; in center injector 32 and similar in all othercharacteristics, excepting an elongated planform configuration, to thenozzle opening 18 described in connection with ejector embodiment 10;

34 and 35; straight-line Coanda injector; each of construction and formcharacteristics similar, except as to planform configuration, to Coandainjector 19 of the FIGS. 1 and 2 arrangement; comprised of a slotted.duct-like straight-line Coanda injector; each projects part of theprimary flow fluid (approximately one-half of the typical 30 to percentproportion of total primary flow) from source 11 into the ejector inletand throat section regions for downward projection essentially along theejector diffuser section interior wall surfaces and for mixing;

36 and 37; Coanda slot opening; straight-line openings in injectors 34and 35 and otherwise similar in characteristics and function to slotopening 20.

Another embodiment of the instant invention is generally similar toembodiment 30 but is not shown in the drawings. Such additionalembodiment differs from the FIGS. 3 and 4 arrangement in that itincludes two center injector assemblies 32 positioned intermediateinjectors 34 and 35 and in spaced-apart relation relative to each other.By this alternate arrangement a proportionately greater center injectionof primary flow fluid can be developed.

FIG. 5 provides quantitative information regarding the performancecapabilities and characteristics of the instant invention. Curves 41 and42 indicate the magnitude of thrust augmentation obtained with theinstant invention at L/D ratios of 2.5 and 2, respectively. Although theinstant invention is important with respect to ejectors having a L/Dratio of 2.5 or less, it is particularly significant with respect toejector apparatus having a ratio (L/D) in the range of approximately 1to 2. In the case of curve 41, which is in part based on actual testdata and in part on theoretical projection, the test embodiment of thecompound ejector was operated with a divergence half-angle (a) of Curve42, on the other hand, involved a divergence half-angle of 12.

The performance of the ejector of this invention, as manifested bycurves 41 and 42, also is compared in FIG. 5 to the performance ofconventional ejectors of comparable design and operating parametershaving only Coanda injection (curves 43 through 45) at 6 half-angledivergence or only conventional center injection (curve 46) at 7.5". Itis apparent from curves 43 through 46 that for comparable ratios ofejector throat area to primary slot area, significantly improved thrustaugmentation ratios are obtained with the present invention. Shorterdesign lengths (L) are achieved by practice of the invention as a resultof permitting utilization of high divergence half-angles (a) withimproved diffuser wall boundary layer control.

In considering the foregoing described invention, careful distinctionmust be made between introducing primary flow fluid into the ejectorsystem by means of a Coanda slot opening in comparison to introducingsuch primary flow fluid into the ejector by tangential g the ejectordiffuser wall as a function of diffuser divergence angle establishedthat in a case of distinct wall separation at a 6 half-angle with centerinjection only, no separation was observed with the additionalintroduction of Coanda slot injection as described in connection withthis invention.

Also, opposed Coanda slot opening injection is considered to efficientlyturn high pressure ratio (e.g. 3.5 to 4) fluid flows over a relativelysmall arc. From the standpoint of effecting Coanda flow turning withoutseparation, the ratio of vane radius or turn curvature adjacent the slotopening to slot height is important and fortunately is not consideredhighly critical. With a small radius to a slot-height ratio(approximately 5), flow detachment from the ejector wall becomesapparent at a pressure ratio of about 1.8 and is based on observeddetachment after about 50 of turning. Increasing the ratio of surfaceturning radius to slot-height functions to improve the obtained thrustaugmentation ratio particularly when at values in the range ofapproximately 10 to 15.

I claim: 1. In ejector apparatus immersed in a body of secondary flowfluid and producing an augmented thrust vector oriented along an ejectorlongitudinal axis, in combination:

perimeter injector means having opposed discharge slots that arepositioned at opposite sides of said longitudinal axis and that areoriented and sized to each discharge primary fluid flowed therethroughin a direction toward and substantially at right angles to saidlongitudinal axis at a discharge velocity greater than approximately 0.7Mach number;

convergent inlet surfaces each extending from immediately adjacent arespective one of said perimeter injector means opposed discharge slotsand continuing in the direction of fluid flow along said longitudinalaxis through a rotational angle in the range of approximately 80 to 1 10to form an ejector apparatus throat having a minimum dimension D in adirection normal to said longitudinal axis;

center injector means having a discharge nozzle that is positionedintermediate said perimeter injector means discharge slots and abovesaid ejector apparatus throat minimum dimension D and that is orientedand sized to discharge primary fluid flowed therethrough in a directiongenerally along said longitudinal axis at a discharge velocity greaterthan approximately 0.7 Mach number;

divergent diffuser surfaces continuing from said convergent inletsurfaces in the region of said ejector apparatus throat minimumdimension D to a termination at an interface with said body of secondaryflow fluid and with an average divergence with respect to each other ofangle 2a; and

duct means flowing high energy primary flow fluid to said perimeterinjector means discharge slots and to said center injector meansdischarge nozzle at pressure ratios greater than approximately 1.3relative to said body of secondary flow fluid and at flow ratessufficient for maintaining said discharge velocities,

said perimeter injector means opposed discharge slots and said divergentdiffuser surfaces termination being separated in a direction along saidlongitudinal axis by a distance L that is less than approximately 2.5times said ejector apparatus throat minimum dimension D, and saiddivergent diffuser surfaces average divergence angle 20: being at leastapproximately 15.

2. The invention defined by claim 1 wherein said opposed discharge slotseach have a height H in the direction of said ejector longitudinal axisand wherein said convergent inlet surfaces each have a mean radius ofcurvature R for said rotational angle, said height H and said radius ofcurvature R being in a ratio substantially in the range of from 1:5 to1:5

3. The invention defined by claim 1 wherein said divergent diffusersurfaces termination is separated from said perimeter injector meansopposed discharge slots in a direction along said longitudinal axis by adistance L that is substantially less than approximately 2.0 times saidejector apparatus throat minimum dimension D.

4. The invention defined by claim 1 wherein said duct means high energyprimary flow fluid is proportioned with approximately from 30 to percentbeing flowed to said center injector means and the balance being flowedto said perimeter injector means.

5. The invention defined by claim 4 wherein said duct means high energyprimary flow fluid is proportioned with approximately 50 percent beingflowed to said center injector means and the balance being flowed tosaid perimeter injector means.

6. The invention defined by claim 1 wherein said divergent diffusersurfaces average divergence angle 20: is at least approximately 24.

7. A method of augmenting the thrust of a primary fluid flow in ejectorapparatus which is immersed in a body of secondary fluid and which hasjoined in succession along a longitudinal axis a convergent inletsection, a throat section of minimum dimension D in a direction normalto said longitudinal axis, and a divergent diffuser section, comprisingthe steps of:

injecting part of said primary fluid flow into said ejector apparatus ina direction generally along said longitudinal axis as a free core jetcentrally of a secondary fluid inlet opening in said convergent inletsection and generally from above and toward said throat section at adischarge velocity greater than approximately 0.7 Mach number andentraining and mixing secondary fluid flowed through said inlet openinginto and with primary fluid from said free core jet;

simultaneously injecting the balance of said primary fluid flow intosaid ejector apparatus in a direction generally at right angles to saidlongitudinal axis as wall jets and from opposite sides of said secondaryfluid inlet opening in said convergent inlet section, toward saidlongitudinal axis, and at discharge velocities greater thanapproximately 0.7 Mach number over opposed curved inlet surfaces in saidconvergent inlet section adjacent thereto;

turning said primary fluid flow injected as wall jets over said curvedinlet surfaces in said convergent inlet section and entraining andmixing additional secondary fluid flowed through said secondary fluidinlet opening in said convergent inlet section into and with the primaryfluid of said wall jets;

diffusing said free core jet and wall jet primary fluid flow andentrained and mixed secondary fluid in said ejector apparatusintermediate opposed wall surfaces extending from said throat sectionand defining said divergent diffuser section; and

discharging said diffused free core jet and wall jet primary fluid flowand entrained and mixed secondary fluid from said ejector apparatus andinto said body of secondary fluid a distance from the region at whichsaid primary fluid flow is injected into said ejector apparatus that isin the direction of said longitudinal axis greater than approximately1.0 times but less than approximately 2.5 times said throat sectionminimum dimension D,

said primary fluid flow and entrained and mixed seconary fluid therebyhaving a thrust at the region of discharge into said body of secondaryfluid at least 50 percent greater in magnitude than the magnitude ofthrust of said primary fluid flow.

8. The method defined by claim 7 wherein said primary fluid flowinjected as a free core jet and as wall jets is injected into saidejector apparatus at a pressure ratio of approximately 1.3 or greaterwith respect to the pressure of said body of secondary fluid.

9. The method defined by claim 7 wherein said primary fluid flowinjected into said ejector apparatus as wall jets has a height in thedirection of said apparatus longitudinal axis in a ratio to the meanradius of curvature of said opposed curved inlet surfaces in saidconvergent inlet section in the range of approximately from 1:5 to 1:5initially.

10. The method defined by claim 7 wherein said primary fluid flowinjected into said ejector apparatus is proportioned in a manner wherebyapproximately from 30 to percent is injected as said free core jet andthe balance is injected as said wall jets.

11. The method defined by claim 7 wherein said primary fluid flowinjected into said ejector apparatus is proportioned in a manner wherebyapproximately 50 percent is injected as said free core jet and thebalance is injected as said wall jets.

12. The method defined by claim 7 wherein said primary fluid flowinjected as wall jets is turned over said opposed curved inlet surfacesin said convergent inlet section through an angle in the range ofapproximately from 30 to 110.

13. The method defined by claim 7 wherein said primary fluid flowinjected as wall jets is turned over said opposed curved inlet surfacesin said convergent inlet section through an angle in the range ofapproximately from to 14. The method defined by claim 7 wherein saidfree core jet and wall jet primary fluid flow and entrained and mixedsecondary fluid is diffused intermediate opposed wall surfaces extendingfrom said throat section that diverge with respect to each other throughan average angle that is at least approximately 15.

15. The method defined by claim 7 wherein said free core jet and walljet primary fluid flow and entrained and mixed secondary fluid isdiffused intermediate opposed wall surfaces extending frorn saidthroatsection that diverge with respect to each other through an averageangle that is at lkeasat apkprokxinlately 24.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,885,891 Dated May 27, 1975 Inventor(s) Lester W. Throndson It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the ABSTRACT, line 7, change "efficient" to efficiency Column 1, line48, after "embodiment" insert l0 Q Column 2, line 56, change "coanda" toCoanda Column 4, line 23, change "opening" to openings Column 6, line19, change "1:5" second occurrence to 1:15

. Column 7, line 34, change "1:5" second occurrence to 1:15

Signed and Scaled this second Day of December1975 [SEAL] Attest:

. RUTH. C. MASON C. MARSHALL DAMN ffi Commissioner oflatents andTrademarks

1. In ejector apparatus immersed in a body of secondary flow fluid andproducing an augmented thrust vector oriented along an ejectorlongitudinal axis, in combination: perimeter injector means havingopposed discharge slots that are positioned at opposite sides of saidlongitudinal axis and that are oriented and sized to each dischargeprimary fluid flowed therethrough in a direction toward andsubstantially at right angles to said longitudinal axis at a dischargevelocity greater than approximately 0.7 Mach number; convergent inletsurfaces each extending from immediately adjacent a respective one ofsaid perimeter injector means opposed discharge slots and continuing inthe direction of fluid flow along said longitudinal axis through arotational angle in the range of approximately 80* to 110* to form anejector apparatus throat having a minimum dimension D in a directionnormal to said longitudinal axis; center injector means having adischarge nozzle that is positioned intermediate said perimeter injectormeans discharge slots and above said ejector apparatus throat minimumdimension D and that is oriented and sized to discharge primary fluidflowed therethrough in a direction generally along said longitudinalaxis at a discharge velocity greater than approximately 0.7 Mach number;divergent diffuser surfaces continuing from said convergent inletsurfaces in the region of said ejector apparatus throat minimumdimension D to a termination at an interface with said body of secondaryflow fluid and with an average divergence with respect to each other ofangle 2 Alpha ; and duct means flowing high energy primary flow fluid tosaid perimeter injector means discharge slots and to said centerinjector means discharge nozzle at pressure ratios greater thanapproximately 1.3 relative to said body of secondary flow fluid and atflow rates sufficient for maintaining said discharge velocities, saidperimeter injector means opposed discharge slots and said divergentdiffuser surfaces termination being separated in a direction along saidlongitudinal axis by a distance L that is less than approximately 2.5times said ejector apparatus throat minimum dimension D, and saiddivergent diffuser surfaces average divergence angle 2 Alpha being atleast approximately 15*.
 2. The invention defined by claim 1 whereinsaid opposed discharge slots each have a height H in the direction ofsaid ejector longitudinal axis and wherein said convergent inletsurfaces each have a mean radius of curvature R for said rotationalangle, said height H and said radius of curvature R being in a ratiosubstantially in the range of from 1:5 to 1:5
 3. The invention definedby claim 1 wherein said divergent diffuser surfaces termination isseparated from said perimeter injector means opposed discharge slots ina direction along said longitudinal axis by a distance L that issubstantially less than approximately 2.0 times said ejector apparatusthroat minimum dimension D.
 4. The invention defined by claim 1 whereinsaid duct means high energy primary flow fluid is proportioned withapproximately from 30 to 70 percent being flowed to said center injectormeans and the balance being flowed to said perimeter injeCtor means. 5.The invention defined by claim 4 wherein said duct means high energyprimary flow fluid is proportioned with approximately 50 percent beingflowed to said center injector means and the balance being flowed tosaid perimeter injector means.
 6. The invention defined by claim 1wherein said divergent diffuser surfaces average divergence angle 2Alpha is at least approximately 24*.
 7. A method of augmenting thethrust of a primary fluid flow in ejector apparatus which is immersed ina body of secondary fluid and which has joined in succession along alongitudinal axis a convergent inlet section, a throat section ofminimum dimension D in a direction normal to said longitudinal axis, anda divergent diffuser section, comprising the steps of: injecting part ofsaid primary fluid flow into said ejector apparatus in a directiongenerally along said longitudinal axis as a free core jet centrally of asecondary fluid inlet opening in said convergent inlet section andgenerally from above and toward said throat section at a dischargevelocity greater than approximately 0.7 Mach number and entraining andmixing secondary fluid flowed through said inlet opening into and withprimary fluid from said free core jet; simultaneously injecting thebalance of said primary fluid flow into said ejector apparatus in adirection generally at right angles to said longitudinal axis as walljets and from opposite sides of said secondary fluid inlet opening insaid convergent inlet section, toward said longitudinal axis, and atdischarge velocities greater than approximately 0.7 Mach number overopposed curved inlet surfaces in said convergent inlet section adjacentthereto; turning said primary fluid flow injected as wall jets over saidcurved inlet surfaces in said convergent inlet section and entrainingand mixing additional secondary fluid flowed through said secondaryfluid inlet opening in said convergent inlet section into and with theprimary fluid of said wall jets; diffusing said free core jet and walljet primary fluid flow and entrained and mixed secondary fluid in saidejector apparatus intermediate opposed wall surfaces extending from saidthroat section and defining said divergent diffuser section; anddischarging said diffused free core jet and wall jet primary fluid flowand entrained and mixed secondary fluid from said ejector apparatus andinto said body of secondary fluid a distance from the region at whichsaid primary fluid flow is injected into said ejector apparatus that isin the direction of said longitudinal axis greater than approximately1.0 times but less than approximately 2.5 times said throat sectionminimum dimension D, said primary fluid flow and entrained and mixedseconary fluid thereby having a thrust at the region of discharge intosaid body of secondary fluid at least 50 percent greater in magnitudethan the magnitude of thrust of said primary fluid flow.
 8. The methoddefined by claim 7 wherein said primary fluid flow injected as a freecore jet and as wall jets is injected into said ejector apparatus at apressure ratio of approximately 1.3 or greater with respect to thepressure of said body of secondary fluid.
 9. The method defined by claim7 wherein said primary fluid flow injected into said ejector apparatusas wall jets has a height in the direction of said apparatuslongitudinal axis in a ratio to the mean radius of curvature of saidopposed curved inlet surfaces in said convergent inlet section in therange of approximately from 1:5 to 1:5 initially.
 10. The method definedby claim 7 wherein said primary fluid flow injected into said ejectorapparatus is proportioned in a manner whereby approximately from 30 to70 percent is injected as said free core jet and the balance is injectedas said wall jets.
 11. The method defined by claim 7 wherein saidprimary fluid flow injected into said ejector apparatus is propoRtionedin a manner whereby approximately 50 percent is injected as said freecore jet and the balance is injected as said wall jets.
 12. The methoddefined by claim 7 wherein said primary fluid flow injected as wall jetsis turned over said opposed curved inlet surfaces in said convergentinlet section through an angle in the range of approximately from 30* to110*.
 13. The method defined by claim 7 wherein said primary fluid flowinjected as wall jets is turned over said opposed curved inlet surfacesin said convergent inlet section through an angle in the range ofapproximately from 80* to 110*.
 14. The method defined by claim 7wherein said free core jet and wall jet primary fluid flow and entrainedand mixed secondary fluid is diffused intermediate opposed wall surfacesextending from said throat section that diverge with respect to eachother through an average angle that is at least approximately 15*. 15.The method defined by claim 7 wherein said free core jet and wall jetprimary fluid flow and entrained and mixed secondary fluid is diffusedintermediate opposed wall surfaces extending from said throat sectionthat diverge with respect to each other through an average angle that isat least approximately 24*.